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MS uses court order to take out Waledac botnet

Zombie network decapitated. For now

Microsoft has won a court-issued take-down order against scores of domains associated with controlling the spam-spewing Waledac botnet.

The software giant's order allows the temporary cut-off of traffic to 277 Internet domains that form command and control nodes for the network of compromised machines. Infected (zombie) machines are programmed to regularly poll these control points for instructions and spam templates.

The .com domains, registered in China, will be sin-binned by VeriSign, at least temporarily decapitating the network. Microsoft estimates that Waledac was one of the 10 largest botnets in the US and a major distributor of spam for online (unlicensed) pharmacies, knock-off goods and other tat, as explained in a blog posting by its legal team here.

Waledac is estimated to have infected hundreds of thousands of computers around the world and, prior to this action, was believed to have the capacity to send over 1.5 billion spam emails per day. In a recent analysis, Microsoft found that between December 3-21, 2009, approximately 651 million spam emails attributable to Waledac were directed to Hotmail accounts alone, including offers and scams related to online pharmacies, imitation goods, jobs, penny stocks and more.

The Microsoft lawsuit also accuses 27 as-yet-unnamed defendants of cybercrime offences associated with the Waledac botnet.

Redmond's techies have followed up the legal action with "ethical countermeasures to downgrade much of the remaining peer-to-peer command and control communication" within the botnet, in partnership with its security firm partners.

Operation b49, as Microsoft dubs the Waledac takedown, still leaves the problem of hundreds of thousands of infected PCs, as Redmond readily acknowledges. Clean-up advice including a suggestion to try out Microsoft's malicious software removal tool is included in the bottom paragraphs of a blog post by Tim Cranton, associate general counsel at Microsoft, here.

Criminals running botnets have faced a number of takedown operations over the last year or so, dating back to the McColo shutdown. All normally result in a temporary slowdown in spam volumes. But cybercrooks are getting better at building more resilient networks. Even if that doesn't work, there are always more miscreants in the shadows ready to step in and sell bulk mail services to unethical, unscrupulous or outright criminal marketeers.

Microsoft's enforcement action is welcome, but it treats only the symptoms - and not the root cause - of the botnet epidemic. ®

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